Question

why do we feel the need to yawn when we see others yawning? the answer may be that our brains are built that way. we automatically copy people, without even thinking about it. it’s our way of being social, or friendly. experts used to think that yawning meant your brain needed oxygen. but a group of scientists proved this idea wrong. they tested the theory by having people breathe in different amounts of oxygen. scientists thought people given more oxygen would yawn a fewer number of times. but the rate of yawning stayed the same for everybody. which word from the passage helps you figure out what \theory\ means? drag it into the box.

Explanation:

To determine the context clue for "theory", we analyze the passage. The sentence "But a group of scientists proved this idea wrong. They tested the theory..." shows that "idea" is used in a similar context as "theory" here, as the scientists are testing the "theory" which was previously referred to as an "idea" (that the brain needed oxygen). So "idea" is the word that helps figure out the meaning of "theory" by providing a context clue of similarity (synonym - like relationship in context).

Answer:

idea